This invention relates to a method for pneumatically supplying preheated coal charges to coking chambers, and to an apparatus for practicing such method, the apparatus permitting a quick separation of the neutral gaseous carrier medium from the preheated coal charges.
Several methods for supplying preheated coal charges to coking chambers are known; only two of such methods have been employed on an industrial scale.
In the first of such two known industrially-applied methods, preheated coal is fed sequentially from individual containers to the coke ovens by means of a special carriage. A special packing system provided between the containers for hot coal and the carriage, and between the carriage and the coke ovens, provides for the safe and dustless feeding of the preheated coal charge at temperatures up to 160.degree. C., and theoretically permits the use of even higher temperatures. Since this feeding is accomplished entirely by gravity, a highly reproducible bulk density of 833 kg/m.sup.3 is achieved. A high accuracy and reliability of charging is necessary with this system, in order to prevent any excessive flow of fine particles into the collecting mains and also to prevent a graphitation of the coke oven.
Another drawback of this apparatus is that the operators of the special carriage must be highly trained; in addition, such operators work in surroundings which are unpleasant and even dangerous, inspite of all safety and hygienic measures which are taken.
The second industrially-applied method of feeding coking chambers with preheated coal charges at a temperature up to 280.degree. C. employs conduits for feeding the coal. When the coke oven is being prepared for the feeding of coal thereinto, a charging container is placed under steam pressure and the preheated coal is supplied to the oven through the feeding conduit in a fluidized state. Individual valves are provided on distributing means associated with the conduit, from which the coal is discharged through lateral openings into the individual coke oven chambers. A gradual filling of the coking chambers is secured by suitable control of the steam pressure which causes the flow of coal in the conduit. Movement of the coal in the conduit and particularly the prevention of its segregation are achieved by the injection of jets of steam into the feeding conduit through nozzles suitably distributed along the active lower part of the conduit. This method is advantageous in that it transports the preheated coal from the charging containers to the coking chambers in a fully safe and dustless manner. A substantial drawback of such method, however, is that a low bulk density is achieved during the filling of the coking chambers with the preheated coal charges, such bulk density being on the order of 660 kg/m.sup.3 ; thus such method entails a lower efficiency of utilization of the space of the coking chambers. Also, in practice there is produced a substantial amount of flue coal dust which is converted to tar; the elimination of such unwanted effects has not yet been satisfactorily accomplished.